/*
* Copyright (c) 2014 Travis Geiselbrecht
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
//#include <asm.h>
//#include <arch/arm/cores.h>
#if defined (__OPTIMIZE_SIZE__)
#if defined (__ARM_ARCH_7M__) || defined (__ARM_ARCH_7EM__)
.global memset
.text
.syntax unified
.thumb
.align 2
/* void *memset(void *s, int c, size_t n); */
.type memset, %function
.thumb_func
memset:
//FUNCTION(memset)
// save the original pointer
push { r0, lr }
// check for zero length
cbz r2, .L_done
// short memsets aren't worth optimizing and make sure we have
// enough headroom to try to do dwordwise move optimization
cmp r2, #16
blt .L_bytewise
// see how many bytes we need to move to align to dword boundaries
and r3, r0, #7
cbz r3, .L_prepare_dwordwise
rsb r3, #8
subs r2, r3
.L_bytewise_align:
// bytewise to align memset
subs r3, r3, #1
strb r1, [r0], #1
bgt .L_bytewise_align
.L_prepare_dwordwise:
// fill a pair of 32 bit registers with the 8 bit value
uxtb r1, r1
orr r1, r1, r1, lsl #8
orr r1, r1, r1, lsl #16
mov r12, r1
// load the number of dwords left
lsrs r3, r2, #3
.L_dwordwise:
// dwordwise memset
subs r3, r3, #1
strd r1, r12, [r0], #8
bgt .L_dwordwise
// remaining bytes
ands r2, #7
beq .L_done
.L_bytewise:
// bytewise memset
subs r2, r2, #1
strb r1, [r0], #1
bgt .L_bytewise
.L_done:
// restore the base pointer as return value
pop { r0, pc }
#endif
#endif